know your patch

central otago has many different habitats within its geographical boundaries

shrub lands and forest

Central Otago had a lot more woody vegetation in prehuman times. Forest, woodland and shrublands existed as a mosaic with small pockets of grassland. There is so little original forest remains that we have to use fossil evidence and look at the margins of Central Otago to imagine what it may been like.

Scrublands would have grown around the margins of the forest especially in the cooler drier spots. Today stands of so called “grey scrub” occur mainly in rocky gullies. These are the hardy survivors of what was once forest and tall scrub. These survivors are here because they are the toughest, the most fire tolerant and inedible of what went before.

So called 'grey scrub' because of its grey look from a distance it is actually made up of a large number of different species featuring lots of different colours -green leaves, yellow flowers and red berries just to name a few. Climbing plants weave their way through a variety of small-leaved, many branched shrubs and small herbs can be found at ground level.

When human induced burning became frequent many fire sensitive forest species were lost forever from the Central Otago landscape but fire tolerant kanuka, an important pioneer species actually increased. Kanuka is able to quickly regenerate due to the substantial seedbank that accumulates in the soil. Decent stands of kānuka dominated forest, can be seen in the Bendigo and Queensberry areas these have been induced by repeated burning of forest vegetation.

Remnant tōtara can also be spotted in a few small communities in the Lauder basin and Waikerkeri conservation areas.

Places to visit -

  • Bendigo scenic reserve - the 'Kānuka Track' is Central's only bush walk

  • Lauder Basin conservation area - Shepherds creek

  • Flat Top Hill conservation area

Examples of what you can find there

grasslands

Grasslands are the other major drylands ecosystem and occur where there is low rainfall and colder temperatures. They are predominantly tussocks but herbs and small shrubs can be found sheltering amongst the clumps. Once they covered up to '31% of the mainland' according to Te Ara encyclopedia of New Zealand, but now 70% of that has been lost and only 3% of the remaining is legally protected (DOC).

They may look lifeless but on closer inspection you can see they support a diverse range of life . Large numbers of insects call this home along with lizards and birds. They are also an important part of soil and water conservation.

Places to visit -

  • Kopuwai conservation area - Old man & Old woman ranges

  • Lauder basin conservation area - Dunstan mountains

  • Oteake conservation area - Manuherikia river valleys

  • Pisa conservation area - Pisa Range

Examples of what you can find there

Chionochloa rigida

Celmisia lyallii

Poa colensoi

alluvial terraces

Long past, ancient riverbeds of Mata-au (Clutha river), the alluvial terraces left behind look barren from a distance but many small threatened plants and rare insects thrive in this semi-arid environment which was once common.

These frosty flats are affected by cold temperature inversion over the winter months and hot sun over summer. With highly porous gravel soils the plants specialised to this area have adapted similar habits to their alpine cousins. Low growing cushion vegetation and tiny shrubs naturally dominate when not outcompeted by exotic weed species.

Grasshoppers, moths, butterflies, native bees, and in summer the cicadas are to be found. Along with the 'Threatened - Nationally vulnerable' banded dotterel and 'At risk - Declining' pipit that make their nests on the ground here.

Land use change, especially over the last two decades has been the major threat to these ecosystems.

Places to visit -

  • Mata-au scientific reserve - Long gully

  • Mahakia Katia scientific reserve - Pisa flats

  • Autaia scientific reserve - Queensberry

  • Alexandra airport - Alexandra

Examples of what you can find there

Pimelea sericeovillosa subsp pulvinaris

Muehlenbeckia ephedroides

Convovulus verecundis

rocky places

Pre human settlement, the big river gorges of Central were once valleys flanked with wooded forest. Moa, tuatara and kakapo amongst other creatures once made this area their home.

The arrival of people with a series of subsequent, devastating fires and weather events has changed all that forever. Rain and wind have stripped the topsoil laying bare the underlying geology of schist rock.

Over the last 600 -750 years other plant species have moved in, adapted and made this steep, rocky terrain their home.

Places to visit -

  • Flat Top Hill conservation area

  • Attfield QEII covenant - Cromwell gorge (permission required)

Examples of what you can find there

Carmichaelia compacta

Luzula species

saline soils

These salty areas once covered over 40,000 ha of Central. Now we have less 100ha remaining. Even this far from the coast, salts from the ocean are brought here by rainwater. In the hot dry climate of Central Otago rainwater that pools on any impermeable surface will potentially develop a salty deposit. These impermeable surfaces are frequently substrates such as ancient lake bed sediments and schist that has been completely weathered to clay.

Gold also accumulated on this layer of clay after working its way through the river gravels and the goldminers in the 1860's targeted these areas, getting well paid for their efforts. This surface was exposed by mining activity and many of our historic reserves are also saline sites.

Rare plants tolerant of high salt environments are found here along with some moths (also endangered). Some of these plants are true halophytes and can sometimes be covered in salt crystals. Other special plants such as the rare spring annuals live here because of there is less competition from weeds. Spring annuals emerge from seed in spring, quickly flower and by the time the hot baking temperatures of summer appear they are gone.

These special habitats are under threat from exotic weed competition, rabbits disturbing the soil and farming. An exciting collaboration with Otago university is coming up where we will see if we can make more 'salty soils' to extend the dwindling areas.

Places to visit -

  • Chapman Road Scientific Reserve - Alexandra

  • Springvale Scientific reserve - Alexandra

Examples of what you can find there

Puccinella raroflorens

Atriplex buchananii

Ceratocephala pungens

streams and wetlands

These are places where water rules and plant and animal life are very specific to the environment.

Wetlands are where the water table is at or near the surface of the land and can be permanent or temporary (ephemeral). Long regarded as pestilential areas that could be put to better use, what better use is there than their natural function! They clean water by trapping sediment and soils and filtering nutrients and contaminants. They return nitrogen to the atmosphere and reduce flooding. They also maintain water tables by acting like sponges.

Not many lowland wetlands now exist in Central and half of those that do are associated with human intervention Eg Bendigo and Butterfields wetlands. A lot of our wetter places especially along river margins are infested with willow.

Our flat topped mountain ranges have numerous tarns and bogs that store water and snow melt to release it slowly throughout the year into our streams. Some of these streams that originate from our 'block' mountains meander across entire valley floors forming 'scroll plains'. The Taieri River scroll plain is one such example of meandering streams and ox bow lakes.

Stream and river edges have their own plant specialists. Some can tolerate waterlogged, dense anaerobic soils while other need moving water and the oxygen that provides. Plants and their preferences can be categorised into zones especially for riparian restoration. These plants also play an important part in water purification and habitat for our aquatic fauna.

Places to visit -

  • Kopuwai conservation area - The head waters of the Fraser river

  • Bendigo wetland - The head of Lake Dunstan

  • Flat Top Hill conservation area - Flat top hill ephemeral wetlands

  • Butterfields wetland - Albert Town conservation area

Examples of what you can find there

Austroderia richardii

Carex secta

Oreobolus pectinatus

Caltha obtusa

alpine areas

Alpine habitats are in the mountains above the area where trees would grow (if we had any bush remnants). These are harsh places with little topsoil, if any, subject to gale force winds and also snow for many months at a time. The change of temperature within a day can be extreme especially in the rocky areas. Special plants and animals have adapted to living in these amazing areas.

Alpine plants response to this is to grow low and slow. Having a dense habit and being covered in hairs are some of the ways they have developed to protect themselves.

Places to visit -

  • Kopuwai conservation area - Old man & Old woman ranges

  • Lauder basin conservation area - Dunstan mountains

  • Oteake conservation area - Hawkdun & St. Bathans ranges

  • Pisa conservation area - Pisa Range

Examples of what you can find up there

Celmisia sessiliflora

Nertera balfouriana

Gentianella amabilis

Leucogenes grandiceps